This disclosure relates to printing systems. Specifically, this disclosure relates to methods and systems to generate profiles for one or more printing devices.
Documents that are representations in either electronic or print format inclusive of color graphics or other illustrative forms are generally created electronically in the “creative” stage of the production workflow with sections from various input devices such as, for example, scanners, cameras, computer graphics, etc. In this workflow, the documents are designed using various layout tools and their color appearance is fine tuned by typically proofing on a workgroup digital printer or the press itself. When the prints are made, it is expected that the appearance on the destination printer follows the proof. If it does not follow the proof, then adjustments are made to many places including color management profile LUTs. One of the key adjustments is the selection of GCR (Gray Component Replacement) methods. The GCR methods fine tune the use of CMYK separations for improving the appearance. Particularly some of the key colors (e.g., black in flesh tones and sky tones) need less black. Sometimes, maximum gamut GCR is preferred over medium GCR to utilize the gamut fully. These adjustments are stored as standard profiles (e.g., ICC profiles).
When a job has already been produced, and a future reprint may be expected, then the color in the future reprint has to be retrieved from the original electronic documents with the original design and the embedded or associated graphics intact.
In image production systems that produce images on a recording medium, such as printers, photocopiers, facsimile machines and other xerographic devices, it is desired to control, as closely as possible, the actual perceived color of the output images. One known method to optimize image color output is to provide a look-up-table (LUT) that translates received color signals into optimized color signals for printing, for example, on a printer.
It is known, for example, that in three-color spaces, such as a Cyan-Magenta-Yellow (CMY) color space, gray color is made up of equal, or near-equal amounts of each one of the colors of the three-color space. Each color in a three-color space which is made up of non-negligible amounts of all three primary colors of the color space can be viewed as having a gray component. Expanding the three-color space to include Black (K) allows then, for most colors in the color space, for a black (K) component to be added in substitution for the gray component. In such a solution, a three-input, four-output LUT is needed.
Another method is discussed in (1) R. Balasubramanian, R. Eschbach, “Design of UCR and GCR strategies to reduce moire in color printing”, IS&TPICS Conference, pp. 390-393 (1999) and (2) R. Balasubramanian, R. Eschbach, “Reducing multi-separation color moire via a variable undercolor removal and gray-component replacement strategy”, Journ. Imaging Science & Technology, vol. 45, no. 2, pp. 152-160, March/April, 2001. A UCR/GCR strategy is proposed that is optimized to reduce moire. In this method, the UCR/GCR strategy is to characterize moire as a function of the color components and to select optimized output color components when the moire function is minimized.